Federal health officials have ordered an Irvine subsidiary of Pfizer Inc. to give special notification to about 350 mechanical heart-valve recipients worldwide who may have been implanted with the potentially defective devices, the company disclosed Monday. Under pressure from lawsuits and the Food and Drug Administration, Shiley Inc.

Shiley Inc., which recalled a batch of heart valves because of a tendency of the devices to fracture, struck an 11th-hour settlement with 259 valve recipients late Wednesday, including a San Diego County woman who took the company to trial. Terms of the agreement were not disclosed. The settlement with Ruth Barillas, a 54-year-old former bank clerk from La Mesa, came hours before a 12-person Orange County Superior Court was scheduled to begin deliberations in the 5-week-old trial.

A consumer group on Wednesday asked the Food and Drug Administration to order an Orange County company to warn users of its mechanical heart valves that the devices might be defective. Public Citizen, a Washington-based organization affiliated with Ralph Nader, estimated that warning notices should go to about 56,000 people with heart valves manufactured by Shiley Inc. of Irvine, a subsidiary of the Pfizer Inc. pharmaceuticals firm.

A state appellate court has ruled that persons with certain heart valves made by Shiley Inc.--a type with a history of life-threatening failures--may sue the manufacturer for fraud even though their valves have not malfunctioned. The Fourth Appellate District Court in Santa Ana on Wednesday reversed the opinion of an Orange County Superior Court judge that Judy Khan of Roanoke, Va., had filed her grievances prematurely because the valve she received in 1983 has not malfunctioned.

A lawyer for more than 300 recipients of potentially defective heart valves is questioning the fairness of a confidential settlement that the manufacturer has apparently negotiated with another group of patients who have filed claims.

Pfizer Inc. said Friday that it is selling most of the product lines of its trouble-plagued Shiley Inc. heart-valve manufacturing subsidiary to an Italian company for an undisclosed price. Shiley's line of cardiovascular products will be sold to the FIAT Group, a diversified industrial company based in Milan with $2 billion in annual revenue. It is not related to the car company. Pfizer, based in New York, expects the deal to close in February.

Pfizer Inc. shareholders filed a lawsuit Monday accusing company executives of withholding information about the financial impact of defects in a mechanical heart valve made by the company's Irvine-based Shiley Inc. unit. Pfizer stock has been battered in recent days because of potential liabilities from defects in a heart valve product that was removed from the market after reports of malfunctions that killed patients. The class-action lawsuit, filed in U.S.

An Anaheim division of a Minneapolis biomedical manufacturer will supply 20,000 blood oxygenators to hospitals in the Soviet Union under a contract that company officials valued at $6 million. Medtronic Cardiopulmonary, a 380-employee division of Medtronic Inc., manufactures the Maxima blood oxygenator, a disposable device used to perform the functions of the lungs during open-heart surgery. Winston R.

The Food and Drug Administration said Thursday that it has asked Shiley Inc. to inform doctors and patients that some of its heart valves are more likely to break than was previously thought. The risk may be great enough, the FDA now says, that some patients may want to undergo risky open-heart surgery to replace the artificial valves. A heart valve fracture is often fatal.

A jury of 10 women and four men was selected Monday to decide whether Shiley Inc. deliberately hid the defects in a controversial artificial heart valve it manufactured that has been linked to the deaths of 300 people. Attorneys for Ruth Barillas, a San Diego resident who received a Bjork-Shiley heart valve more than 10 years ago, will try to persuade the Orange County Superior Court jury that Barillas was the victim of fraud by Shiley and its parent, Pfizer Corp. of New York.